In a casual format the goal is to have fun. Sure, we are all still playing to win eventually but the journey is worth more than the end goal. The definition of well-designed changes when you are designing a deck for others.

You are to become the Shaper of the Cosmos. It is you who will give form and content to the all the universe. You will breathe life into the stillness, giving meaning and purpose to all the actions which are to follow. - Gary Gygax